Structure and spectroscopic study of aqueous Fe(III)-As(V) complexes using UV-Vis, XAS and DFT-TDDFT
Structure and spectroscopic study of aqueous Fe(III)-As(V) complexes using UV-Vis, XAS and DFT-TDDFT
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DOI：
10.1016/j.chemosphere.2017.05.018
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发表时间：
2017-09-01
期刊：
影响因子：
8.8
通讯作者：
Yi, Haibo
中科院分区：
文献类型：
--
作者：
Chai, Liyuan;Yang, Jinqin;Yi, Haibo
铁（Fe（III））和砷酸盐（As（V））之间的水溶液络合物对于理解砷（As）在富Fe（III）-As（V）体系中的流动性是必不可少的。通过对Fe（III）-As（V）-HClO_4和Fe（III）-As（V）-H_2SO_4体系的紫外-可见光谱的定性分析，推测了Fe（III）-As（V）水溶液中存在FeH_2AsO_4 ~（2+）和FeHAsO_4 ~（2+）两种配合物。随后，通过Fe K边EXAFS证实了单齿结构，并通过DFT模拟为[FeH 2AsO 4（H2O）（5）]（2+）和[FeHAsO 4（H2O）（5）]（+）。在280 nm附近的特征谱带被证实主要是由Fe-As桥氧原子对[FeH_2AsO_4（H_2O）（5）]（2+）和[FeHAsO_4（H_2O）（5）]（+）中Fe的d轨道的电子激发。Fe（III）-As（V）配合物的结构和光谱信息将使未来的Fe（III）-As（V）富集体系的形态分析成为可能。(C)2017由Elsevier Ltd.出版
Aqueous complexes between ferric (Fe(III)) and arsenate (As(V)) are indispensable for understanding the mobility of arsenic (As) in Fe(III)-As(V)-rich systems. In this study, aqueous Fe(III)-As(V) complexes, FeH2AsO42+ and FeHAsO4+, were postulated based on the qualitative analysis of UV-Vis spectra in both Fe(III)-As(V)-HClO4 and Fe(III)-As(V)-H2SO4 systems. Subsequently, monodentate structures were evidenced by Fe K-edge EXAFS and modeled as [FeH2AsO4(H2O)(5)](2+) and [FeHAsO4(H2O)(5)](+) by DFT. The feature band at similar to 280 nm was verified as electron excitation chiefly from Fe-As-bridged O atoms to d-orbital of Fe in [FeH2AsO4(H2O)(5)](2+) and [FeHAsO4(H2O)(5)](+). The structural and spectral information of Fe(III)-As(V) complexes will enable future speciation analysis in Fe(III)-As(V)-rich system. (C) 2017 Published by Elsevier Ltd.